Diverse studies have shown that the behavioral, cellular and physiological functions of animals can be affected by magnetic stimuli. Weak magnetic fields exert a variety of biological effects ranging from alterations in cellular ion flux to modifications of animal orientation and learning, and therapeutic actions in humans. It is desirable to understand the effects of low intensity magnetic fields on humans as these magnetic fields are normally present in man-made environments. Devices and systems that emit such magnetic fields include telephones, headphones, computers and monitors, AC adapters, electrical fans, electric motors, hair dryers, cellular phones and other wireless communications devices, transmitter towers, power transmission lines and transformers, televisions, radios and compact disc (CD) players, to name but a few.
There are several theories addressing the mechanism of the effect that magnetic field exposure has on tissues. For example, low frequency magnetic field exposures have been proposed to exert their effect(s) through induction of electric currents. Although not widely believed, it has also been proposed that weak magnetic fields are detected by particles of magnetite in tissue and, by virtue of this detection, have a physiological effect.
Although the mechanism of the effects of magnetic field exposure on tissues is uncertain, it is clear that magnetic fields are a physical agent which have little attenuation in tissue and therefore, can be used to alter endogenous processes provided the magnetic fields can be detected and their detection coupled to a physiological process. In view of this, it is desired to expose subjects to magnetic fields to treat physiological, neurological and behavioral disorders and to determine the effect of a variety of magnetic stimuli on subjects.
An apparatus for generating electromagnetic waveforms to stimulate a subject is described in U.S. Pat. No. 6,312,376, to Koren et al. This apparatus includes an electromagnetic waveform signal generator that generates an analog waveform signal representing desired electromagnetic waveforms to be used to stimulate the subject. A selector is responsive to channel select input and applies the analog waveform signal to selected output channels of the selector. Electromagnetic field generators, coupled to the output channels of the selector, convert the analog waveform signal into electromagnetic waveforms thereby to expose the subject wearing the electromagnetic field generators to the desired electromagnetic waveforms. Although this apparatus works well, improvements in devices of this nature are desired.
It is therefore an object of the present invention to provide a novel apparatus and method for generating electromagnetic waveforms to stimulate a subject.